[dknightx]

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so ... what happens if we set up the cameras to watch the slits, and we bring two people into the room.

Person A does not know the cameras are set up and can see the screen. What does he see?

Person B knows the cameras are set up, but can't see the screen. Afterwards, he takes the camera, falls down and the film is destroyed. He returns to the screen, what does he see?

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Do A and B ever communicate with each other?


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no they never communicate with each other (nor do they even know someone else is in the room) until after they have both seen the screen for the first time.

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At this point in time, Person A returns, does what he see differ than what he saw earlier?

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I didn't know A ever left? What difference would that make? The screen cannot magically change from what he has previously seen.

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Ok well this question isn't that important, but the question is if A will observe the particle pattern even if he does not know the slit is being observed AND the film is destroyed in the future (but before the film is actually destroyed).